Although recent studies of adult cancer patients have found that radiation therapy to the neck is a significant risk factor for carotid artery disease and stroke, this adverse late-effect of radiation therapy has not been well-studied in survivors of childhood cancer. This pilot study will obtain preliminary data on the association between carotid artery disease and neck irradiation and other associated risk factors in 30 long-term survivors of childhood cancer who received radiation therapy to the neck and 30 healthy related age- and gender-matched control subjects. The study also will evaluate the feasibility of conducting a subsequent larger study aimed at assessing the risks associated with radiation-induced carotid artery disease. Specific Aims: 1. Determine the feasibility of obtaining ultrasound-based measurements of carotid intima-media thickness (C-IMT) and carotid arterial wall stiffness (C-AWS) in pediatric cancer survivors who were treated with neck irradiation and in matched related healthy controls; 2. Investigate the differences in prevalence of carotid artery disease, as measured by C-IMT and C-AWS, in childhood cancer survivors who received radiation therapy to the neck and in matched related healthy controls; 3. Collect preliminary data on the relationship between C-IMT and C-AWS measurements and radiation dose and time since treatment in pediatric cancer survivors; and 4. Collect preliminary data on the prevalence of cardiovascular risk factors that may be related to carotid artery disease, such as obesity, dyslipidemia and smoking, in cancer survivors who received neck irradiation and in matched related healthy controls. Understanding this potential radiation-induced late-effect will help guide the development of long-term follow- up guidelines for this population of childhood cancer survivors. Early identification of high-risk individuals provides the opportunity for timely implementation of preventive measures, such as counseling on diet, smoking and physical activity, to decrease the risk of and the significant morbidity and mortality associated with advanced carotid artery disease.